Circuit substrates, particularly active matrix substrates, are widely used in active matrix display devices such as EL (electroluminescence) display devices. Circuit substrates used in conventional liquid crystal display devices had TFT (thin film transistor) elements at respective intersections of a plurality of scan signal lines disposed so as to intersect with a plurality of data signal lines. Image signals are sent as appropriate to respective pixels (electrodes) that are connected to TFT elements due to the switching function of the TFT elements. Furthermore, there are circuit substrates having storage capacitance elements for respective pixels in order to prevent degradation of image signals due to electric discharge or OFF current of the TFT elements while the TFT elements are OFF, and also to use as a path or the like for applying various modulated signals during liquid crystal driving.
Below is an example of a conventional structure of a circuit substrate. Disclosed is a display device provided with an island shaped gate disconnection repairing conductive layer used for repairing disconnections, which includes: a plurality of gate wiring lines provided on a substrate; a first insulating layer provided on the gate wiring lines; a plurality of source wiring lines disposed so as to intersect with the gate wiring lines with the first insulating layer therebetween; an island shaped gate disconnection repairing conductive layer used to repair disconnections in the gate wiring lines disposed over the gate wiring lines with the first insulating layer therebetween; switching elements provided at the intersections of the gate wiring lines and the source wiring lines; a second insulating layer provided over the source wiring lines, the gate disconnection repairing conductive layer, and the switching elements; a contact hole provided in a portion of the second insulating layer; and pixel electrodes connected to the switching elements through the contact holes (see Patent Document 1, for example).
As a thin film transistor array by which it is possible to repair disconnections in a similar manner, a thin film transistor is disclosed, including: a plurality of scan signal lines formed of a first conductive film on a transparent insulating substrate; a plurality of signal lines formed of a second conductive film; pixel electrodes formed on a gate insulating film in an area surrounded by adjacent scan signal lines and adjacent signal lines; thin film transistors connected to the pixel electrodes; and a light-shielding film that is formed of the first conductive film and that forms a light-shielding overlapping portion through surrounding portions of the respective pixel electrodes and the gate insulating film, the surrounding portion facing the signal lines, wherein the light-shielding film has a prescribed area located near both edges thereof along the signal line, the area protruding towards so as to form an overlapping portion for repairing through the signal lines and the gate insulating film (see Patent Document 2, for example).
Furthermore, liquid crystal display devices that can electrically connect disconnected wiring lines or that can improve the yield of the connection is improved by electrically connecting the disconnected wiring lines and making the connection of the circuits and the panel terminal electrodes easy (see Patent Documents 3 to 5, for example.)